Scientists at Massachusetts Institute of Technology have completed what is believed to be the first major study to assess the greenest way of drying your hands.

The research paper compared the seven most common drying methods in public toilets and concludes that paper towels and warm air hand dryers have the highest environmental toll – generating 70% more carbon emissions than the newest technology on the market, the cold air-driven hand dryer from UK manufacturer Dyson, which also commissioned the paper.

The study could also help conumers in comparing the environmental impact of products by distinguishing greenwash and making it easier to interpret the growing number of environmental claims. Last year Dyson and US paper towel corporation Kimberly Clark were involved in a row over research, which suggested “significant hygiene risks associated with jet air dryers and warm air dryers”, which Dyson dismissed as false claims.

MIT’s new research looked at the entire life cycle of various competing products from cradle to grave – materials, manufacturer, use and end of life – including use of transport, dispenser, waste bins and bin liners. Previous scientific studies into hand drying have tended to focus on the spread (and usually increase) of bacteria, amid growing concern about infection control and the impact of superbugs on public health.

Consumers typically perceive recycled paper towels to be better for the environment. But the report’s researchers found that the environmental impact of recycled towels equals that of virgin paper towels in a number of environmental measures, including CO2 emissions and and water consumption. In the US, 2% of total landfill consists of paper towels. Recycled and virgin towels were both found to generate over three times more carbon emissions than the Dyson Airblade hand dryers, creating waste, consuming more energy and also using more water.

By contrast, the environmental impact of warm air hand dryers occurs during use. Energy-heating elements and inefficient motors tip the sustainability scales, making warm air dryers up to 80% less energy-efficient than the Dyson Airblade hand dryer.

Sir James Dyson, the billionaire founder of Dyson and inventor of the bagless vaccuum cleaner, claimed the findings were an independent endorsement for his product, which is now available in 34 countries worldwide, with sales growing by nearly 70% last year. He commented: “Paper towels and warm hand dryers – like vacuum bags – are from a byegone era. Technology has moved on. People want to dry their hands quickly, competely and without damaging the environment .”

The Dyson Airblade was launched in the UK in October 2006, when it was heralded as more hygienic, more energy-efficient and more than twice as fast as any conventional electric hand dryer on the market. In the UK, it has gained a Carbon Trust rating, reflecting its green credentials.

MIT’s paper has been peer reviewed and the work will soon be submitted for publication in a leading academic journal.

Source http://www.guardian.co.uk/environment/2011/nov/11/paper-towels-drying-hands-energy